CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

Problem simulating natural convection tall cavity

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   September 24, 2014, 16:11
Unhappy Problem simulating natural convection tall cavity
New Member
Join Date: Sep 2014
Posts: 1
Rep Power: 0
natalialissette is on a distinguished road
I hope someone can help me.

I'm trying to simulate natural convection in a tall vertical annuli cavity. Height is 0.215 m, outer cylinder is 0.15 m, and inner cylinder is 0.03 m in diameter.

My mesh is al hexahedral 2D, with 70700 elements. My model is 2D axysimetric. There are more than 30 elements in the region of the boundary layer.

Gravity is -9.81 in X. I'm using double precision in Fluent. Pressure-based solver, steady. I'm using SST k-omega with low Re-correction. I'm doing the boussinesq approximation stating operating density and a compresibility coefficient. Fluid is water.

The boundary conditions are uniform heat flux 440 w/m^2K in the inner wall and -176 W/m^2K for the outer wall. The Rayleigh number is 10^8. Scheme SIMPLE, Spatial discretization for pressure is PRESTO!, second order upwind for momentum, turbulence, dissipation and energy. All relaxation factors are default. I doesn't converge. k is constanlty diverging.

I also tried transient approaches and it seems to converge only at low Ra numbers. I have tried other solvers, and other models for viscosity and nothing seems to work.

Can someone give me suggestions??

Thanks in advance
natalialissette is offline   Reply With Quote


boussinesq approximation, fluent, high rayleigh numbers, natural convection, tall cavity

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
convergence problem in natural convection paps ANSYS 0 December 1, 2013 05:04
Natural convection in cavity heated by below Nanbrain Main CFD Forum 0 January 28, 2013 07:49
how to set the parameters in simulating the natural convection hook FLUENT 1 January 17, 2010 01:33
Radiative heat transfer with natural convection inside a square cavity msarkar OpenFOAM 1 January 11, 2010 22:21

All times are GMT -4. The time now is 00:36.